BACKGROUND
Obesity is a disease of fat storage and reduced fasting fat utilisation, commonly assessed from respiratory quotient (RQ) using indirect calorimetry (IC), and impacts weight management and health (1). Measurement of changes in RQ could provide a basis for individualised nutrition and lifestyle intervention (2). Previously we have demonstrated that 67% of subjects present to clinic with suboptimal RQs and have highlighted the limited value of fat utilisation assumptions in overweight and obese individuals (3).
OBJECTIVES
To assess the value of RQ measurement over time in the clinical setting and following on from our previous poster we investigated the one week follow up RQ of overweight and obese individuals (n=214), and more specifically those with an initial RQ > 0.81 (n=152), to assess the impact of dietary change on RQ.
MATERIAL & METHODS
We conducted a retrospective analysis of the metabolic data of overweight and obese individuals using ECAL, an IC developed by MHS (4). RQ was measured during initial testing and follow up testing following dietary modification (20% CHO load) of between 5-14 days. Subjects were instructed to observe a minimum of 4 hours fasting time before the test, following a protocol developed for clinical practice (5).
RESULTS
Overall there was a strong negative correlation between the initial RQ and the change in RQ from first to second test r = -0.544 (p < 0.005). Of those with an initial RQ > 0.81, 112 (73.7%) lowered their RQ of which 58 (38.2%) had normalised by the second test. 40 subjects (26.3%) showed either no change or an increased RQ from first to second test.
CONCLUSION
The significant group of non-responders highlights the multi-factorial nature of obesity and the requirement for further investigation, specifically pathology. Indirect calorimetry and RQ measurement can be used as tools to identify the reasons behind poor fat utilisation, improving patient outcomes and providing mechanisms for an individualised approach to obesity management.